The present invention relates to a method for producing a wrench socket and, more particularly, to a method for producing a wrench socket having size indicia by direct pressing.
U.S. Pat. Nos. 4,839,059 and 4,947,713 both to Arnold discloses an elastomeric sleeve mounted to a rear portion of a wrench socket. The elastomeric sleeve is integrally molded from a suitable plastic, rubber or other elastomeric material. The elastomeric sleeve is provided with suitable size indicia formed by integral casting or molding. A suitable adhesive secures the sleeve on the socket and precludes an axial separation therebetween. In another embodiment disclosed in U.S. Pat. No. 4,839,059, a pressure-sensitive laminated label is bonded to the sleeve and includes size indicia formed by impression stamping, printing, engraving or other methods. However, the size indicia is not directly formed on the sleeve and involves complicated manufacturing procedures, leading to waste of time and costs.
U.S. Design Pat. No. 442,837 to Porras discloses a grippable drive socket having knurls on an outer periphery thereof and size indicia formed in the outer periphery by rolling. U.S. Pat. No. 6,761,093 to Chang and U.S. Patent Publication No. 2006/0090612 A1 also disclose socket having size indicia formed on the outer periphery by rolling. However, the distance from the size indicia to the outer periphery of the socket must be limited to avoid damage to the structural strength and/or mechanical properties of the hollow socket formed by rolling. As a result, the size indicia is liable to be damaged due to impact or abrasion.
U.S. Pat. No. 7,028,588 to Shih discloses a tool including a rectangular area formed on a cylindrical outer surface thereof. An identification mark or numeral is formed on the rectangular area as a representation of a size of the tool. The rectangular area and the numeral have different colors. The numeral is formed by cutting through the rectangular area to form a stencil for exposing a metal color of the tool and providing a contrast of the numeral to other portions of the area. Deformation of the tool resulting from stamping is avoided. However, formation of the numeral by cutting to form a stencil is much complicated and expensive. Furthermore, the numeral thus formed has a film-like structure that is liable to be damaged or become blurred due to impact or abrasion.
A need exists for a method for producing a wrench socket with size indicia that is more resistant to impact and/or abrasion.